In this respect, a method for producing gear teeth having a required crowning and a required twist is shown in EP 1 995 010 B1. For this purpose, a crowned tool is used on the one hand, which is manufactured in that the spacing between the dressing wheel and the worm is varied on the dressing of the grinding worm during the shifting of the worm in the direction of its axis. In this respect, a certain axial spacing is implemented at the worm center and is increased or decreased toward the two worm ends in accordance with the square of the spacing from the worm center. In addition, during the diagonal feed grinding process, the axial spacing between the grinding worm and the workpiece is changed to produce a crowned modification. A possible embodiment is furthermore mentioned in which the modification resulting from the combination is determined via a simulation of the production process on a computer, wherein the modifications should be changed iteratively such the required crowning and the required twist are achieved. How such an iteration could take place and how the tool required could be manufactured is, in contrast, not specified in EP 1 995 010 B1. The twist itself is determined via the difference of profile angle differences in two different planes.
A method is furthermore known for producing a modified gear tooth geometry from DE 10 2012 015 846 A1 in which the desired modification of the surface geometry of the workpiece on the tooth flank has a constant value in the generating pattern at least locally in a first direction of the workpiece and is given by a function f(x) in a second direction of the workpiece which extends perpendicular to the first direction. In this respect, for manufacturing this modification of the surface geometry of the workpiece, a modification of the surface geometry of the tool is used which has a constant value in the generating pattern at least locally in a first direction of the tool and is further optionally given by the same function f(cx), optionally compressed linearly by a factor c, in a second direction of the tool which extends perpendicular to the first direction. The modification on the tool is provided in that one or more specific corrections of the axial movement with respect to the conventional dressing kinematics are carried out in dependence on the angle of rotation of the tool and/or on the tool width. Furthermore, with a predefined macrogeometry of the tool and a given line of action of the dressing tool, the axial feed of the workpiece and/or the shift movement of the tool and/or the compression factor c is/are selected such that the modification of the tool along a line G1, on which the contact point moves on the tool during the machining of the workpiece, corresponds to the desired modification of the workpiece along a line G2 on which the contact point on the workpiece moves. It is furthermore specified that these corrections can be superposed on the correction movements such as are known from the prior art.
It is the object of the present disclosure to improve the methods known from the prior art for the manufacture of a workpiece having a corrected gear tooth geometry and/or a modified surface structure and to provide corresponding calculation methods, dressing methods, gear manufacturing machines or computer systems.
This object is achieved by the independent claims of the present disclosure. Advantageous embodiments of the disclosure form the subject of the dependent claims.
In accordance with a first aspect, the present disclosure comprises a method for the manufacture of a workpiece having a corrected gear tooth geometry and/or a modified surface structure by a diagonal feed generating method by means of a modified tool. In this respect, a specific modification of the surface geometry of the tool is produced. The specific modification of the surface geometry of the tool have a constant value in the generating pattern at least locally in a first direction of the tool and can be given by a function FFt1 in a second direction of the tool which extends perpendicular to the first direction. Alternatively or additionally, the specific modification can be produced in that the position of the dresser to the tool is varied during the dressing in dependence on the angle of rotation of the tool and/or on the tool width position. The specific modification of the tool generates a corresponding modification on the surface of the workpiece by the diagonal generating method. Provision is made in accordance with the present disclosure in this respect that the modification produced by the specific modification has a profile modification and/or a modification caused by a variation of the machine kinematics during the machining process superposed. By the combination with a profile modification and/or a modification caused by a variation of the machine kinematics during the machining process, substantially more modifications can be produced in accordance with the present disclosure than by the specific modification alone. The inventor of the present disclosure has recognized in this respect that the individual modifications can be superposed and are simply additive without any mutual influence. Since corresponding methods for the manufacture of the individual modifications are available, they only have to be combined with one another for manufacturing the superposed modification.
The modification produced by the specific modification is optionally superposed with a profile modification. The profile modification of the workpiece in particular be produced by a correspondingly profile-modified tool. The profile modification of the tool can in turn be produced by a correspondingly modified dresser.
In this respect, a combination of modifications is optionally determined which approximates or even exactly produces the desired modification.
The form and/or proportions and/or parameters of the respective modifications can furthermore optionally be determined by a curve fitting.
In accordance with a second aspect, the present disclosure comprises a method for the manufacture of a workpiece having a corrected gear tooth geometry and/or a modified surface structure by a diagonal generating method by means of a modified tool, wherein a desired modification of the surface geometry of the workpiece is predefined and, on the basis of the desired modification of the surface geometry of the workpiece, a specific modification of the surface geometry of the tool is determined which produces a modification on the surface of the workpiece by the diagonal generating method. Provision is made in accordance with the present disclosure that the form of the specific modification of the surface geometry of the tool and/or at least one, and optionally a plurality of parameters of the machining process and/or of the macrogeometry of the tool are determined by curve fitting.
In accordance with this aspect of the present disclosure, the curve fitting is therefore used to determine with respect to a desired modification on the surface of the workpiece that specific modification of the surface geometry of the tool and/or at least one, and optionally a plurality of parameters of the machining process and/or of the macrogeometry of the tool on whose use (optionally in combination with other modifications) the desired modification can be approximately or even exactly produced.
In accordance with the second aspect, the modification produced by the specific modification of the surface geometry of the tool can represent the only modification. In a possible embodiment, however, it can also be superposed with other modifications. This can in particular take place such as is shown in more detail with respect to the first and third aspects.
In accordance with the second aspect, the form of the specific modification of the surface geometry of the tool and/or the diagonal ratio and/or the axial cross angle during the diagonal generating method and/or of the cone angle and/or of the profile angle of the tool may be determined. In this respect, the form of the specific modification of the surface geometry of the tool and the diagonal ratio are in particular determined.
In a first variant, a diagonal ratio constant over the tool width can be determined in this respect. The diagonal ratio influences the orientation of the modification on the workpiece. If therefore work is carried out with a constant diagonal ratio, the modification on the workpiece typically has the same orientation, i.e. the same first direction, in which the modification is constant over the total tooth width.
In a second variant, the diagonal ratio can, however, also be determined as a non-constant function of the feed position. It is hereby possible to produce an even wider spectrum of modifications. A modification can thus in particular be produced on the workpiece whose orientation varies over the tooth width or which differs in different regions of the tooth flank.
In this respect, work can in particular be carried out using different diagonal ratios for machining different regions of the workpiece.
In this respect, in a first variant, work can be carried out with a constant diagonal ratio within the respective regions. In this respect, two or more regions can in particular be determined or predefined within which a respective constant diagonal ratio is determined, with the diagonal ratios of at least two regions being able to differ. The number and/or arrangement of the regions and the respective diagonal ratios can further be determined.
Alternatively, the diagonal ratio can be determined at least in a region of the axial feed as a steady, non-constant function of the axial feed. The diagonal ratio in particular be freely determined in dependence on the axial feed at least within certain conditions.
In this respect, the specific modification of the tool can have a constant value in the generating pattern at least locally in a first direction of the tool and can be given by a function FFt1 in a second direction of the tool which extends perpendicular to the first direction. Alternatively or additionally, the specific modification can be produced in that the position of the dresser to the tool is varied during the dressing in dependence on the angle of rotation of the tool and/or on the tool width position.
In accordance with a third aspect, the present disclosure comprises a method for the manufacture of a workpiece having a corrected gear tooth geometry and/or a modified surface structure by a modified tool. In this respect, for the manufacture of the workpiece, at least two different modifications are superposed which can be generated by a modification of the dressing process of the tool and/or of the dresser used for dressing the tool and/or of the machining process of the workpiece. Provision is made in accordance with the present disclosure that a desired modification of the workpiece is divided by curve fitting at least approximately into at least two different modifications of the workpiece.
The desired modification of the workpiece is thus divided into different portions in accordance with the present disclosure. The division may take place such that the different modifications of the workpiece determined by the curve fitting can each be manufactured by one of the following three methods: By a modification of the dressing process of the tool; by a modification of the dresser used for dressing the tool; and/or by a modification of the machining process of the workpiece.
The modifications of the workpiece determined in accordance with the present disclosure may be used to determine the modifications of the dressing process of the tool and/or of the dresser used for dressing the tool and/or of the machining process of the workpiece required for the production of said modifications of the workpiece determined in accordance with the present disclosure. The method in accordance with the present disclosure thus has two steps in that first the desired modification of the workpiece is divided into different modifications of the workpiece and the modifications of the dresser, of the dressing process or of the machining process, which are required for the individual modifications, are only determined after this division.
The desired modification may be divided into at least one first modification which can be produced by a modification of the dressing process of the tool and into a second or third modification which can be produced by a modification of the dresser used for dressing the tool or by a modification of the machining process of the workpiece.
The three aspects of the present disclosure be used independently of one another. In a preferred embodiment of the present disclosure, however, at least two and optionally all three aspects are used in combination. In this respect, the determination of the specific modification of the surface geometry of the tool and/or of at least one, and optionally a plurality of parameters of the machining process and/or of the macrogeometry of the tool provided in accordance with the second aspect can in particular also take place in the course of the curve fitting optionally provided in accordance with the first or third aspects.
All three processes in accordance with the present disclosure have substantial advantages over the prior art in this respect. Unlike the iteration process anyway only mentioned in passing in EP 1 995 010 in which an adaption to the desired values is attempted via a simulation of the production process and via an iteration, the three processes in accordance with the present disclosure actually allow a good approximation of a desired modification and in some important cases even an exact production of the desired modification. For while EP 1 995 010 does not present any strategy on how the iteration could take place or how the tools underlying the simulation would be able to be manufactured and is thus not practical, the present disclosure actually provides the skilled person with the possibility of producing a plurality of desired modifications.
The fact be utilized in accordance with the present disclosure that the modifications resulting from the different types of production have different dependencies on the coordinates in the generating pattern and therefore complement one another. In this respect, the present disclosure already considers the manufacturing ability of the modifications from the start.
At least two of the following modifications may be superposed in accordance with the methods in accordance with the present disclosure shown above:                a first modification of the surface of the workpiece which is produced by a specific modification of the surface geometry of the tool which is in turn produced in that the position of the dresser to the tool on the dressing is varied in dependence on the angle of rotation of the tool and/or on the tool width position and/or which has a constant value in the generating pattern at least locally in a first direction of the workpiece and is given by a function FFt2 in a second direction of the workpiece;        a second modification of the surface of the workpiece which is produced by a profile modification of the dresser; and/or        a third modification of the surface of the workpiece which is produced by a variation of the machine kinematics during the machining process of the workpiece.        
Alternatively or additionally, the shape and/or the portions and/or the parameters of the respective modification are determined by curve fitting in which a predefined, desired modification is divided at least approximately into at least two of the following modifications:                a first modification which has a constant value in the generating pattern at least locally in a first direction of the workpiece and is given by a function FFt2 in a second direction of the workpiece which extends perpendicular to the first direction;        a second modification which is given by a pure profile modification; and/or        a third modification which has a constant value in the generating pattern at least locally in a third direction of the workpiece and is given by a function FKFt in a fourth direction of the workpiece which extends perpendicular to the third direction.        
The present disclosure makes use of the fact that the first, second and third modifications have a specific dependence on the coordination in the generating pattern and each be manufactured by the corresponding methods.
In this respect, in accordance with the first and third aspects, in accordance with the present disclosure, a desired modification may be predefined and that combination of modifications is determined by means of the curve fitting which ideally approximates and/or exactly produces the desired modification. In some applications, which are by all means relevant, an exact division of the desired modification into the first, second and/or third modifications can be determined in this respect. In other, even more complex modifications, in contrast, an approximation to the desired modification which is as ideal as possible is produced by the curve fitting.
In accordance with the second aspect, in accordance with the present disclosure, a desired modification may be predefined and those parameters of the machining process and/or of the macrogeometry of the tool and/or that specific modification of the surface geometry of the tool is determined by means of the curve fitting which ideally approximates and/or exactly produces the desired modification. In some applications, which are by all means relevant, an exact production of the desired modification will be able to be achieved by a corresponding choice of the specific modification of the surface geometry of the tool and of the parameters of the machining process and/or of the macrogeometry of the tool. In other, even more complex modifications, in contrast, an approximation to the desired modification which is as good as possible is produced by the curve fitting.
The desired modification can in this respect, for example, be predefined as a continuous function and/or at a plurality of points.
The form of the specific modification or the form of the individual modifications may further be determined at a plurality of points and/or as a continuous function.
The generating pattern can in particular also be covered by a spot cloud here on which the modifications are determined or the modification are presented as a continuous function over the total generating pattern. The modification is this respect optionally determined at more than ten points in the generating pattern, further optionally at more than 100 points in the generating pattern. The desired modification and/or the modifications produced by the division is/are further optionally specified or determined as a function of the position in the generating pattern.
The plurality of points or the spot cloud produced by them may span a surface on the tooth flank. If the modification is given as a continuous function or if it is determined as such, this function may be defined at least on a part surface of the tooth flank, or optionally over the total tooth flank. The modification is thus in particular no longer only predefined or determinable on certain lines, but areally.
In addition to the above-presented methods for the manufacture of a workpiece having a desired modification, the present disclosure furthermore comprises corresponding methods for the determination of the specific modification of the surface geometry of the tool used for this purpose or of the combinations of modifications required for this purpose required for manufacture of a workpiece having a desired modification of the gear tooth geometry and/or of the surface structure.
In accordance with the first aspect of the present disclosure, this comprises a method for the determination of the combination of modifications required for the manufacture of a workpiece having a desired modification of the gear tooth geometry and/or of the surface structure, wherein a specific modification of the surface geometry of the tool which has a constant value in the generating pattern at least locally in a first direction of the tool and is given by a function FFt1 in a second direction of the tool which extends perpendicular to the first direction, has a profile modification and/or a modification caused by a change of the machine kinematics during the machining process superposed on it, wherein a desired modification is predefined and that combination of modifications is determined by means of curve fitting which ideally approximates and/or exactly produces the desired modification.
In accordance with the third aspect, the present disclosure comprises a method for the determination of the specific modification of the surface geometry of the tool used for this purpose required for the manufacture of a workpiece having a desired modification of the gear tooth geometry and/or of the surface structure, with the machining process being a diagonal generating method in which the specific modification of the surface geometry of the tool produces a modification of the surface geometry of the workpiece. In this respect the form of the specific modification of the surface geometry of the tool and/or at least one, and optionally a plurality of parameters of the machining process and/or of the macrogeometry of the tool is/are determined by curve fitting.
In accordance with the third aspect of the present disclosure, it comprises a method for the determination of the combination of modifications required for the manufacture of a workpiece having a desired modification of the gear tooth geometry and/or of the surface structure, wherein a predefined, desired modification is at least approximately divided into at least two of the following modifications:                a first modification of the surface geometry of the workpiece which can be produced by a specific modification of the tool during the dressing and which has a constant value in the generating pattern at least locally in a first direction of the workpiece and is given by a function FFt2 in a second direction of the workpiece which extends perpendicular to the first direction;        a second pure profile modification which can be produced by the shape of the dresser; and/or        a third modification which can be produced by a change of the machine kinematics during the machining process and which has a constant value in the generating pattern at least locally in a third direction of the workpiece and is given by a function FKFt in a fourth direction of the workpiece which extends perpendicular to the third direction.        
The advantages which were described above with respect to the manufacturing methods in accordance with the present disclosure also result by the methods in accordance with the present disclosure for the determination of the specific modification of the tool and/or of the combinations of modifications required for the manufacture of the workpiece. The methods in accordance with the present disclosure in particular be used for the determination of the modifications in the course of such manufacturing processes. The determination methods in accordance with the present disclosure can furthermore be configured such as has already been shown above with respect to the manufacturing processes.
The desired modification of the workpiece may be freely selected at least within certain conditions. The methods in accordance with the present disclosure allow an at least approximate production of almost any desired modifications.
The form of the respective modification may be selected freely at least within certain conditions in the course of the division or of the curve fitting of the respective modification while taking account of its respective dependence on the coordinates in the generating pattern. This is possible in accordance with the present disclosure because the present disclosure takes account of the manufacturing ability of the modifications from the start.
The first direction of the first modification may be freely selected at least within certain conditions together with the second direction as part of the curve fitting.
One and optionally a plurality of parameters of the machining process and/or of the macrogeometry of the tool can furthermore optionally be freely selected within certain conditions. The diagonal ratio and/or the axial cross angle during the diagonal generating method and/or the cone angle and/or the profile angle of the tool in particular be freely selected.
In contrast, the third and fourth directions which determine the third modification may be predefined by the base helical angle of the workpiece. The third and fourth direction can therefore not be adapted as part of the curve fitting.
In a possible embodiment of the present disclosure, the possible values of the functions can be restricted by conditions as part of the curve fitting. The possible values for the first or second direction of the first modification in particular be restricted. The possible values for the diagonal ratio can furthermore be restricted.
The maximum variation of the functions describing the modifications can furthermore be restricted. Restrictions which result from the respective production methods can hereby also be taken into account.
In accordance with the present disclosure, a distance function can be used as part of the curve fitting in accordance with the first and third aspects, said distance function quantifying the difference between the total modification given by the sum of the respective modifications and the desired modification.
In accordance with the present disclosure, a distance function can be used as part of the curve fitting in accordance with the second aspect, said distance function quantifying the difference between the modification produced by the specific modification of the tool on the surface of the workpiece and the desired modification. This is the case if no other modifications are used.
As part of the curve fitting, the distance function thus allows a quantification of the quality of the approximation by the selected modifications.
The distance function may carry out a mean value formation over a plurality of points in the generating pattern or over the total generating pattern. In particular when the modifications are determined over a plurality of points, a mean value formation over these points is sufficient as a distance function. In contrast, the mean value formation is optionally carried out over the total generating pattern on the determination of continuous functions as modifications. The mean value formation optionally takes place over all points at which the modification is determined.
The distance function can, for example, be the sum or an integral over the difference present at the individual points between the sum of the respective modifications and the desired modification. In this respect, this difference can be determined identically for all points in the generating pattern, for example as a square of the difference.
As part of the curve fitting, however, a distance function A(wF, zF) can also be used which depends on the generating path wF and on the tooth width position zF. The differences can hereby be weighted differently in different regions of the workpiece.
A weighted distance function in particular be used as part of the curve fitting, wherein differences in specific regions of the workpiece are optionally weighted more strongly than differences in other regions. Differences in those regions in which the tolerances of the surface geometry of the workpiece are larger are optionally weighted less than differences in those regions in which the tolerances are smaller.
Provision is made in accordance with the present method that that specific modification of the surface geometry of the workpiece which has a constant value in the generating pattern at least locally in a first direction and is given by a function FFt2 in a second direction of the workpiece is determined as part of the curve fitting which, optionally together with at least one further modification, optimally approximates and/or exactly produces the desired modification, wherein the modification of the surface geometry of the tool required for this purpose and/or the machine kinematics required for this purpose during the dressing is/are determined from the specific modification of the surface geometry of the workpiece. The specific modification of the surface geometry of the tool may have a constant value at least locally in a first direction of the tool and is given by a function FFt1 in a second direction of the tool which extends perpendicular to the first direction and/or is produced in that the position of the dresser to the tool is varied during the dressing in dependence on the angle of rotation of the tool and/or on the tool width position.
The function FFt1 on the tool is optionally the same function, optionally compressed linearly by a factor, as the function FFt2 on the workpiece. The linear compression relate to the argument of the function and/or to the magnitude of the function. In this respect, the sign of the function naturally changes between the workpiece and the tool since raised points on the tool produce lowered points on the workpiece and vice versa. In the normal section, in particular FFt1(x)=−FFt2 (cx) can apply in this respect, i.e. there is only compression with respect to the argument; an additional constant factor k can in contrast be present in the transverse section with respect to the magnitude of the function, i.e. FFt1(x)=−k*FFt2 (cx). The factors k and c be larger than or less than 1 depending on the specific conditions.
In this respect, in particular a pure profile modification and/or a modification which can be produced by the machine kinematics during the machining process of the workpiece can in particular be considered as a further modification. The first modification in accordance with the present disclosure which is produced by the modification of the dressing process of the tool used for machining the workpiece is optionally produced in the diagonal generating method. This modification is optionally produced such as is already known from DE 10 2012 015 846 A1.
In accordance with the present disclosure, as part of the curve fitting, the form and/or the portion and/or the parameters of at least one and optionally two or three of the possible modifications is/are optionally varied to determine that combination of modifications which approximates the desired modification as ideally as possible and/or exactly produces it. In this respect, the form of the function FFt1/2 and/or of the function FKFt and/or of the profile modification and/or the first direction of the first modification can in particular be varied.
Alternatively or additionally, in accordance with the present disclosure, as part of the curve fitting, at least one and optionally a plurality of parameters of the machining process and/or of the macrogeometry of the tool and/or the form of the specific modification of the tool can be varied to determine those parameters and/or that modification which approximate the desired modification as ideally as possible and/or exactly produces it. The form of the function FFt1/2 and/or the first direction of the first modification and/or the diagonal ratio and/or the axial cross angle during the diagonal generating method and/or of the cone angle and/or of the profile angle of the tool can in particular be varied in this respect.
The form of the function FFt1/2 and the diagonal ratio can in particular be varied in this respect.
In a first variant, in this respect, a diagonal ratio can be provided which is constant over the tool width and whose value is varied as part of the curve fitting.
In a second variant, the diagonal ratio can, however, also be defined as a non-constant function of the feed position. In this respect, work can in particular be carried out using different diagonal ratios for machining different regions of the workpiece.
In this respect, in a first variant, work can be carried out with a constant diagonal ratio within the respective regions. In this respect, two or more regions can in particular be predefined within which the value of a respective constant diagonal ratio is determined, with the diagonal ratios of at least two regions being able to differ. The number and/or arrangement of the regions and the respective diagonal ratios can furthermore be varied.
Alternatively, the diagonal ratio can also be defined as an at least sectionally steady, non-constant function of the axial feed and can be varied. The diagonal ratio in particular be freely varied in dependence on the axial feed at least within certain conditions.
In the present disclosure, as part of the first modification, both specific modifications of the surface geometry of the tool can be taken into account which can be produced by a dressing with only one stroke and those modifications which are produced by the dressing in a plurality of strokes. The same applies to the second modification which can be produced by a profile modification of the dresser.
The present disclosure furthermore comprises a method for the dressing of a tool by which a tool for a method in accordance with the present disclosure for the manufacture of a workpiece can be provided or by which the combination determined by a determination method in accordance with the present disclosure can be implemented. In this respect, on the one hand, a specific modification of the surface geometry of the tool is produced by a variation of the machine kinematics during the dressing process in dependence on the angle of rotation of the tool and/or on the tool width position. On the other hand, a modified dressing tool is additionally used to produce a profile modification. The variation of the machine kinematics during the dressing process in particular take place in that one or more of the following corrections of the axial movements relative to the conventional dressing kinematics are carried out.                a) Variation of the axial spacing of the dresser from the tool in dependence on the angle of rotation of the tool or on the tool width (delivery)        b) Variation of the axial feed of the tool or of the dresser in dependence on the angle of rotation of the tool or on the tool width (shift)        c) Variation of the axial cross angle of the tool and of the dresser in dependence on the angle of rotation of the tool or on the tool width (pivot)        d) Variation of the tool speed in dependence on the angle of rotation of the tool or on the tool width.        
The dressing method in accordance with the present disclosure thus allows the production of a superposition of a first and second modification in accordance with the manufacturing method or determination method in accordance with the present disclosure.
The present disclosure can in principle also be used with non-dressable tools. In this case, the modifications of the tool are already produced during the manufacture of the tools and cannot be changed during the machining process of a workpiece.
In case of a non-dressable grinding tool, the inventive modification of the surface geometry can be produced during the manufacturing process in exactly the same way as described in the following for dressable tools, with the only change that instead of a dressing tool, a corresponding manufacturing tool is used, for example a rolling die.
In case that the tool is a hobbing cutter, it has to be manufactured in such a way that the enveloping body of the hobbing cutter has the modification provided by the present disclosure. With respect to a hobbing cutter, the term “modification of the surface geometry of the tool” as used in the context of the present disclosure is to be understood as a modification of the surface geometry of the enveloping body of the hobbing cutter.
The present disclosure may be used with a dressable tool. In particular, the modification of the surface geometry of the tool may be generated during a dressing step.
The present disclosure furthermore comprises a gear manufacturing machine for the carrying out of a manufacturing method in accordance with the present disclosure and/or for the carrying out of a dressing method in accordance with the present disclosure. The gear manufacturing machine advantageously has an input and/or calculation function via which the kinematic variations of the machine kinematics can be predefined and/or can be determined during the machining process and/or dressing process and/or a control function which varies the machine kinematics during the machining process and/or the dressing process. The gear manufacturing machine in accordance with the present disclosure in particular be configured such that a superposition of a first and third modification can be produced in accordance with the manufacturing or calculation method in accordance with the present disclosure.
The input function may allow the input of a desired modification, while the calculation function determines the modification required for its manufacture and/or the variations of the machine kinematics required for the production of the modification during the machining process and/or dressing process.
The gear manufacturing machine in accordance with the present disclosure is further optionally a gear grinding machine. The gear grinding machine optionally has a tool spindle, a workpiece spindle and/or a spindle for the reception of a dresser, in particular of a dressing wheel, and machine axes for carrying out the relative movements required in accordance with the present disclosure between the workpiece and the tool and/or between the tool and the dresser in accordance with the present disclosure.
The present disclosure furthermore comprises a computer system and/or a software program for determining the combination of modifications required for the manufacture of a workpiece having a desired modification. The computer system or the software program comprises a function for the predefinition of a desired modification and further comprises a curve fitting function.
In accordance with the first and third aspects, the curve fitting function determines a combination of modifications which approximates the desired modification as ideally as possible and/or determines it exactly.
The curve fitting function is designed in accordance with the first aspect such that it determines a modification of the workpiece and its combination with a profile modification and/or of a modification caused by a variation of the machine kinematics during the machining process which can be produced by a specific modification of the surface geometry of the tool so that the combination approximates the desired modification as ideally as possible and/or produces it exactly.
The curve fitting is designed in accordance with the second aspect such that it determines the form of a specific modification of the surface geometry of the tool and/or of at least one, and optionally a plurality of parameters of the macrogeometry of the tool and/or at least one, and optionally a plurality of parameters of a diagonal generating method which approximates the desired modification as ideally as possible and/or can produce it exactly.
The curve fitting function is designed in accordance with the third aspect such that it divides a predefined, desired modification of the workpiece by curve fitting at least approximately into at least two different modifications of the workpiece which can each be produced by a modification of the dressing process of the tool and/or of the dresser used for dressing the tool and/or of the machining process of the workpiece.
The computer system and/or software program in accordance with the present disclosure thus implement(s) the curve fitting function in accordance with the present disclosure.
The computer system or software program may furthermore comprises a calculation function which determines the modifications of the dressing process of the tool and/or of the dresser used for dressing the tool and/or of the machining process of the tool required for the production of the modifications from these modifications of the workpiece determined in this manner.
The curve fitting function may be configured such that it divides the desired modification at least approximately into at least two of the following modifications:                a first modification which has a constant value in the generating pattern at least locally in a first direction of the workpiece and is given by a function FFt2 in a second direction of the workpiece which extends perpendicular to the first direction;        a second modification which is given by a pure profile modification; and/or        a third modification which has a constant value in the generating pattern at least locally in a third direction of the workpiece and is given by a function FKFt in a fourth direction of the workpiece which extends perpendicular to the third direction.        
The computer system and/or software program in accordance with the present disclosure may be configured such that it/they implement(s) one of the above-presented methods. The curve fitting function in particular have the functions which were already described above with respect to the methods in accordance with the present disclosure.
The computer system in accordance with the present disclosure have an interface to a gear manufacturing machine and can communicate the control parameters and/or control commands required for the carrying out of a method in accordance with the present disclosure to the gear manufacturing machine. The software program in accordance with the present disclosure can be installable on a gear manufacturing machine to program it to carry out a method in accordance with the present disclosure.
It is optionally a gear manufacturing machine in accordance with the present disclosure such as was presented above.
The variations of the machine kinematics during the machining process and/or dressing process may be predefined and/or determined by the computer system and/or the software.
Deviations of the gear tooth geometry from involute gear teeth may be considered as modifications in accordance with the present disclosure. In this respect, it can be a question of gear teeth having both straight teeth and having slanted teeth. The gear teeth can be both symmetrical and asymmetrical, i.e. be the profile angles of the left and right flanks can, but do not have to be different.
The manufacturing method in accordance with the present disclosure is may be used in diagonal feed generating grinding. A grinding worm may be used as a tool. The dressing optionally takes place via a profile roller dresser. The dressing of the tooth flank take place in one or more strokes.
The profile roller dresser in particular be in contact with the tooth of the tool from the root region to the tip region during dressing so that the modification takes place in one stroke over the total tooth depth.
The profile roller dresser can alternatively only be in contact with the tooth of the tool in part regions between the base and the tip during the dressing so that the modification takes place in a plurality of strokes over the tooth depth.
The dressing of the tooth tip can take place via a tip dressing tool.
The tool have a cylindrical basic shape in a first variant of the present disclosure. In this case, the axial cross angle during the diagonal generating method and the profile angle of the tool do not have any effect on the modification and are therefore also not varied or determined as part of the curve fitting. With a cylindrical tool, however, the diagonal ratio can be varied or determined as part of the curve fitting.
The tool have a conical basic shape in a second variant of the present disclosure. In this case, the axial cross angle during the diagonal generating method and the profile angle and the cone angle of the tool have effects on the modification and can therefore optionally likewise be varied or determined as part of the curve fitting.
The tool in accordance with the present disclosure having a conical basic shape may have involute gear teeth which can, however, optionally have a modification. Involute gear teeth have a geometry which is produced by the generating machining step between a cylinder and a rack. The conical basic shape is produced in that the axis of rotation of the cylinder is tilted toward the main plane of the rack in the course of this generating machining step.
In accordance with a preferred embodiment, the cone angle of the tool is greater than 1′, further optionally greater than 30′, and further optionally greater than 1°. The cone angle of the tool is, however, optionally less than 50°, optionally less than 20°, and further optionally less than 10°.
The diagonal ratio be constant over the total tooth width in a first variant so that a variation or determination only takes place with respect to the size of the diagonal ratio.
The diagonal ratio can have different values over the tooth width in a second variant.
In this respect, two or more regions having different diagonal ratios can be provided. The diagonal ratio again be constant within the regions. In this case, a variation or determination can take place with respect to the number of the regions and/or the position of the regions and/or the respective magnitude of the diagonal ratio.
The diagonal ratio can furthermore also be given by a function of the position in the tooth width direction which is optionally freely selectable within certain conditions and which is optionally at least sectionally steady. Even more possibilities hereby result in the variation.
The present disclosure will now be explained in more detail with reference to embodiments and Figures.
The Figures only show w-z diagrams of cylindrical gear teeth by way of example. The w-z diagrams of conical gear teeth are generally not rectangular, are typically trapezoidal, since the evaluation region of the generating path varies over the gear tooth width.